Scrafty is certainly an interesting Pokemon with its great dual typing, decent defenses, great abilities and movepool and above all, its ability to stick around for a while. Its sub-par speed is also a boon when using or dealing with Trick Room, and with Fake Out in its arsenal it makes a great lead.
Single sets:

@ Sitrus/Chople Berry
Jolly nature
252 atk / 252 spe / 4 HP
hi jump kick/drain punch
dragon dance
ice punch
crunch
(yeah i never played singles with scrafty so someone help me out here)
Double sets:
Fake Out lead

@ Chople Berry
Adamant/Brave nature
Moxie
252 HP / 252 Attack / 6 SpD
Fake Out
Drain Punch
Crunch
Detect
The premise of this set is to allow your partner time to set up Trick Room or similar moves, or simply make sure a Terrakion doesn't Rock Slide your Rock-weak partner. Detect is generally preferred over Protect as it cannot be Imprisoned bar Smeargle and Zoroark, but if you find your battles are more drawn out and you need the extra 8 PP, then use Protect. Drain Punch is part of the reason for Scrafty's longevity, keeping Scrafty healthy while doing damage. Crunch is there for STAB, but if you need the coverage, Scrafty also learns Fire, Thunder and Ice Punch as well. Bear in mind, however that if you opt for Fire or Ice Punch, you will be walled by Pokemon like Jellicent and Chandelure.
The type resistant berries make Scrafty even more annoying to deal with, as when the opponent tries in vain to OHKO Scrafty with Close Combat or Flight Gem Acrobatics, Scrafty lives and heals off the damage with Drain Punch, possibly getting the offending Pokemon into KO range for your partner. If you have Scrafty's weaknesses covered by your team, You can try Lum and Sitrus Berries to keep Scrafty from being Burned, put to sleep or simply restoring health in tandem with Drain Punch. Moxie is generally the preferred ability given Scrafty's resilience, but if you like first-turn wake-ups or being able to shrug off Toxic, Shed Skin is an option.
Other options Scrafty can use are Iron Ball+Fling, more Speed and Life Orb. Life Orb adds a little extra punch to your moves, and with Drain Punch healing off the recoil, it's a very viable option. Fling with Iron Ball can be used to underspeed other Trick Room teams, but you're outpaced by other Scrafty outside of Trick Room and vulnerable to be Faked Out first. Iron Ball is useless with Fling if the opponent decides to Protect on your Fling, which wastes your Iron Ball and an entire moveslot for the rest of the battle. You can run more Speed, specifically 98 and 180 Speed to outspeed unboosted base 125 and 130 speed Pokemon under Tailwind, respectively. If you're not going to make use of the surprise that comes with a Scrafty outspeeding Crobat, however, there are better Fake Out users you can use.
someone help me out here, i've never played GBU singles with this guy, and is there really any other useful doubles set for him?